<div><div id="page-canvas" style="height: calc(100vh - 1.5rem - 41px); border: 1px solid"></div><div v-on:click="changeBtn()" style="right: 10vw; position: absolute; top: 15vh; color: white; background: #03a9f499; border: 1px solid #2196F3; padding: 3px 10px; cursor: pointer">切换 </div></div>